Snail Lymnaea Acuminata Research Articles

Toxicity of Pesticides to Fecundity, Hatchability and Survival of Young Snails ofLymnaea acuminata

AbstractThe effects of carbaryl and phorate on the fecundity and hatchability of the snailLymnaea acuminata, the survival of young snails were studied. It was observed that the fecundity ofLymnaea acuminatawas reduced only at the 11.00 mg/l concentration of carbaryl and phorate, whereas a time‐ and dose dependent reduction in the hatchability of exposed eggs and the survival of young snails was observed.

Correlation of the anticholinesterase and molluscicidal activity of the latex of Euphorbia royleana on the snail Lymnaea acuminata.

Correlation of the anticholinesterase and molluscicidal activity of the latex of Euphorbia royleana on the snail Lymnaea acuminata.

Alteration in biogenic amine levels in the snail Lymnaea acuminata by the latex of euphorbia royleana

The latex of Euphorbia royleana which has high molluscicidal and anti-cholinesterase activity against Lymnaea acuminata reduced the levels of 5-hydroxytryptamine (5HT) and dopamine (DA) in the nervous tissue of L. acuminata. There was, however, no significant change in the level of 5-hydroxyindole acetic acid (5HIAA). The changes were found to be dependent on concentration of the latex extract. Similar changes were produced by both water and organic solvent extracts of the latex. The latex of E. royleana thus affects all the known neurotransmission mechanisms in the snail either separately or through a complex interaction between the different neurotransmitters. This may account for its high toxicity to snails.

Inhibition kinetics of certain organophosphorus and carbamate pesticides on acetylcholinesterase from the snail Lymnaea acuminata

k 2, Kd and k i, for 2 organophosphorus (Phorate and Formothion) and 2 carbamate pesticides (Mexacarbate and Carbaryl) using acetylcholinesterase present in homogenates of the nervous tissue of the snail Lymnaea acuminata, were determined. Calculation of zero time velocities demonstrated that even in their P-S form the organophosphate compounds inhibited snail acetylcholinesterase. The kinetic constants of the 2 carbamates have been explained on the basis of their structure. The toxicity of the 4 pesticides has been explained on the basis of their kinetic constants.

In vivo andIn vitro studies on synergism with anticholinesterase pesticides in the snailLymnaea acuminata

The synergistic effects of piperonyl butoxide (PB)2, sulfoxide (SU), and dimethyl amino aniline (DAA) used in conjunction with two organophosphate pesticides (phorate and formothion) and two carbamate pesticides (mexacarbate and carbaryl) were examined in terms of the LC50 and acetylcholinesterase (AChE) inhibition in the snailLymnaea acuminata. The three synergists reduced the LC50 of phorate, formothion, mexacarbate, and carbaryl at exposure periods ranging from 24 to 144 hr. PB and SU had strong synergistic action; DAA had little effect; the highest synergistic ratio (70) was found with carbaryl and PB. The synergists enhanced thein vitro inhibition of cholinesterase caused by the pesticides; the synergistic effect onin vitro inhibition, however, was lower, compared to the change in the LC50.

Busulphan and thiourea as chemosterilants for the snail lymnaea acuminata

AbstractTreatment of the snail Lymnaea acuminata with an alkylating agent (busulphan) or a thiocarbamide (thiourea), for 3 days, significantly reduced the number of eggs and prevented embryonic development. Both the drugs caused a dose dependent reduction in the levels of protein, DNA, RNA and the activity of the alkaline phosphatase of the ovotestis, and a dose‐dependent enhancement in the levels of amino‐acids and the activity of the acid phosphatase. Discontinuation of the drug treatment for 7 days resulted in a near complete recovery in DNA and RNA levels, while there was no change in the levels of protein, amino‐acids and the activities of the acid and alkaline phosphatases.

Chemosterilization and its reversal in the snail Lymnaea acuminata.

Treatment of the snail Lymnaea acuminata, the vector for the liver flukes Fasciola hepatica and Fasciola gigantica, with two alkylating agents (cyclophosphamide and busulfan) and one thiocarbamide (thiourea) caused reduction in the number of eggs and production of non-viable embryos. All the three drugs caused reduction in the levels of DNA, RNA and protein and the activity of alkaline phosphatase in the gonadal tissues of this snail. There was enhancement in free amino acid levels and activity of acid phosphatase by these drugs. Discontinuation of treatment could not reverse the cytotoxic effects of these drugs. Treatment of sterilized snails with prostaglandin E1 (PGE1), prostaglandin F2 alpha (PGF2 alpha) or hydrogen peroxide not only restored the number of eggs but also caused full embryonic development. Also, there was near total recovery of RNA, DNA and protein levels and small changes in free amino acid levels as well as the activity of alkaline and acid phosphatase. It has been suggested that the prostaglandins play a modulatory role in protein synthesis. The possible therapeutic use of PGE1, PGF2 alpha and H2O2 has been pointed out.

Phorate and mexacarbate induced changes in enzymes of the snail,Lymnaea acuminata

The snailLymnaea acuminata, vector of the liver flukesFasciola hepatica andFasciola gigantica, was exposed to 40% and 80% LC50 doses of the pesticides 12/24 mg/L phorate (O,O-diethylS-(ethylthio) methyl phosphorodithioate) and 2.5/5.0 mg/L of mexacarbate (4-dimethylamino)-3,5-dimethylphenyl methyl carbamate) for 24 or 48 hr. These pesticides, although considered to be antiacetylcholinesterase agents, inhibited alkaline phosphatase and enhanced the activity of acid phosphatase in hepatopancreas, mantle, intestine, and foot of the snail. Trypsin activity in the alimentary canal of the snail was also inhibited. Discontinuation of pesticide treatment resulted in partial recovery in mexacarbate-treated animals while in phorate-treated animals the effect of the pesticide was largely irreversible.

Changes induced by phorate in the carbohydrate metabolism of the snail Lymnaea acuminata

AbstractCarbohydrate metabolism was studied in the hepatopancreas, mantle, intestine and foot of the snail Lymnaea acuminata, exposed to 40% and 80% of the LC50 dose of phorate (12 and 24 mg litre−1, respectively) for 24 and 48 h. Following treatment with the pesticide, the rate of oxygen consumption and the glycogen contents were reduced, while the levels of lactic acid and reducing sugars were enhanced. Withdrawal of the pesticide for 7 days after exposure of the snails to 12 mg of phorate litre−1 for 48 h did not reverse these changes.

Cyclophosphamide as a potential chemosterilant for harmful snails.

Cyclophosphamide induced changes in the ovotestis of the snail Lymnaea acuminata, the vector of the giant liverflukes Fasciola hepatica and Fasciola gigantica were studied in order to explore potential of the drug as a chemosterilant for snails. The drug caused a dose dependent reduction in the levels of DNA, RNA and proteins and the activity of the enzyme alkaline phosphatase. It increased the activity of acid phosphatase and the levels of total free amino acids in the ovotestis. While the animals showed nearly total recovery in RNA and DNA levels 7 days after termination of drug treatment, changes produced in protein, amino acid levels and phosphatase activity did not show any recovery. It appears that cyclophosphamide, while affecting its primary targets i.e. DNA and RNA, irreversibly inhibits protein synthesis through other cellular enzymes as well.